Neuroscience research
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Neuroscience research · Jul 2014
An analysis of cerebral blood flow from middle cerebral arteries during cognitive tasks via functional transcranial Doppler recordings.
Functional transcranial Doppler (fTCD) is a useful medical imaging technique to monitor cerebral blood flow velocity (CBFV) in major cerebral arteries. In this paper, CBFV changes in the right and left middle cerebral arteries (MCA) caused by cognitive tasks, such as word generation tasks and mental rotation tasks, were examined using fTCD. CBFV recordings were collected from 20 healthy subjects (10 females, 10 males). ⋯ Furthermore, both types of cognitive tasks produced higher values in most signal features. Geometric tasks were more distinguished from the rest-state than verbal tasks and the lateralization was exhibited in right MCA during geometric tasks. Our results show that the raw CBFV signals provided valuable information when studying the effects of cognitive tasks and lateralization in the MCA.
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Neuroscience research · Apr 2014
Basal μ-opioid receptor availability in the amygdala predicts the inhibition of pain-related brain activity during heterotopic noxious counter-stimulation.
The aim of this study was to investigate the association between the magnitude of anti-nociceptive effects induced by heterotopic noxious counter-stimulation (HNCS) and the basal μ-opioid receptor availability in the amygdala. In 8 healthy volunteers (4 females and 4 males), transcutaneous electrical stimulation was applied to the right sural nerve to produce the nociceptive flexion reflex (RIII-reflex), moderate pain, and scalp somatosensory evoked potentials (SEPs). Immersion of the left hand in cold water for 20min was used as HNCS. ⋯ Besides, HNCS did not induce significant changes in pain and RIII-reflex amplitude (p>0.05). These results suggest that activation of μ-opioid receptors in the amygdala may contribute to the anti-nociceptive effects of HNCS. The lack of RIII-reflex modulation further suggests that μ-opioid receptor activation in the amygdala contributes to decrease pain-related brain activity through a cerebral mechanism independent of descending modulation.
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Neuroscience research · Feb 2014
Involvement of Wnt/β-catenin signaling in the development of neuropathic pain.
Despite tremendous research effort in the field, our current understanding of the molecular mechanisms underlying neuropathic pain is still incomplete. In the present study, our objective was to elucidate the involvement of the Wnt/β-catenin signaling pathway in the development of neuropathic pain. We showed that Wnt/β-catenin signaling is activated in the spinal cord dorsal horn after partial sciatic nerve ligation (PSL). ⋯ Moreover, we also found that PSL-induced microglial activation was significantly suppressed by intrathecal administration of XAV939 treatment. Because it was revealed that Wnt3a treatment triggered brain-derived neurotrophic factor (BDNF) release from microglial cells in vitro, it is possible that Wnt3a upregulation in the dorsal horn leads to the activation of microglial cells, then triggers BDNF secretion that is responsible for the establishment of neuropathic pain. Further studies will be needed for the comprehensive understanding of the roles of Wnt/β-catenin signaling in the development of neuropathic pain.
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Neuroscience research · Jan 2014
Development and pharmacological verification of a new mouse model of central post-stroke pain.
Central post-stroke pain (CPSP) including thalamic pain is one of the most troublesome sequelae that can occur after a cerebrovascular accident. Although the prevalence of CPSP among stroke patients is relatively low, the persistent, often treatment-refractory, painful sensations can be a major problem and decrease the affected patient's quality of life. To better understand of the pathophysiological basis of CPSP, we developed and characterized a new mouse model of thalamic CPSP. ⋯ Behavioral analysis demonstrated that the animals displayed diclofenac-, morphine- or pregabalin-resistant mechanical allodynia and thermal hyperalgesia of the hind paw contralateral to the lesion for over 112 days. However, we found that minocycline, a microglial inhibitor, significantly ameliorated mechanical allodynia and thermal hyperalgesia. These results suggest that this model might be proved as a useful animal model for studying the neuropathology of thalamic syndrome, and developing improved therapeutics for CPSP.
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Neuroscience research · Sep 2013
Potentiation of quantitative electroencephalograms following prefrontal repetitive transcranial magnetic stimulation in patients with major depression.
The long-lasting effects of repetitive transcranial magnetic stimulation (rTMS) on electroencephalogram (EEG) activity are not clear. We aimed to investigate the cumulative rTMS effects on EEG and clinical outcomes in patients with major depression. Twenty-five patients with medication-resistant depression underwent 10 daily rTMS sessions over the left dorsolateral prefrontal cortex. ⋯ In an ANOVA model, including all prefrontal electrodes, post hoc analyses revealed significant time effects on the theta (F1,24 = 7.89, P = 0.010; +43%), delta (F1,24 = 6.58, P = 0.017; +26%), and alpha (F1,24 = 4.64, P = 0.042; 31%) bands without site specificity. Clinical correlations were observed between F4 alpha power increases and improvements in HAM-D retardation, F3 alpha power increases and improvements of the absolute changes in perseveration and error number on the WCST, and C3 and C4 theta power increases and improvements of the percent change in perseveration and error number on the WCST following rTMS. Consecutive prefrontal rTMS could induce long-lasting EEG potentiations beyond the aftereffects, resulting in improved cognitive and depressive symptoms.